Control apparatus for subsurface well tools



2 Sheets-Sheet 1 IN V EN TOR.

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J. D. KEITHAHN CONTROL APPARATUS FOR SUBSURF'ACE WELL TOOLS Feb. 20,1962 original Filed May 19, 19.58 FG Feb, 20, 1962 J. D. KEITHAHN3,021,902

CONTROL APPARATUS FOR SUBSURFACE WELL TOOLS Original' Filed May 19, 19582 Sheets-Sheet 2 if .4a

.Fi/Go f INVENTOR.

dente rater 3 021,902 CQNTRQJ AFPARTUS FR SUBSURFACE WELL TSLS uiianKeithahn, Anaheim, Calif., assigner to Baker @il Tools, lne., LosAngeles, Calif., a corporation or California @riginal application May19, 1958, Ser. No. 736,133, npw Patent Nm 2,975,837, dated Mar. 21,1961. Divided and this application Jan. 20, 1959, Ser. No. 737,955

it? Slairns. (Cl. 16e-237) The present invention relates to subsurfacewell bore equipment, and more particularly to control orclutch apparatusfor governing the operation of the equipment in the well bore.

The present application is a division of my application for FrictionDrag Devices, Serial No. 736,138, tiled May 19, 1958.

An object of the invention is to provide a well tool adapted foroperation in a well bore and embodying an improved clutch device forselectively uncoupllng parts to permit relative longitudinal movementtherebetween, or coupling such parts for joint longitudinal movement ata plurality of longitudinal positions that the parts can occupy withrespect to each other.

Another object of the invention is to provide a clutch or latch devicefor selectively controlling relative longitudinal movement between partsof a subsurface well bore tool, and embodying a clutch element capableof being relatively located in a position to engage clutch or ratchetteeth extending along a member or in a position to engage a smoothportion of such member, wherein the clutch element is disengaged fromthe member.

This invention possesses many other advantages, and has other objectswhich may be made more clearly apparent from a consideration of a formin which it may be embodied. This form is shown in the drawingsaccompanying and forming part of the present specilication. lt will nowbe described in detail, for the purpose of illustrating the generalprinciples of the invention; but it is to be understood that suchdetailed description is not to be taken in a limiting sense, since thescope of the invention is best deiined by the appended claims.

Referring to the drawings:

FIGURE 1 is a longitudinal section through the apparatus, with its partsin retracted position, and with the clutch in engaged condition;

FIGURE 2 is an enlarged longitudinal section through the apparatus shownin FIGURE l, with certain parts expanded against the well casing andwith the clutch in disengaged condition;

FIGURE 3 is an enlarged fragmentary longitudinal section through aportion of the apparatus;

FIGURE 4 is an enlarged cross-section taken along the line 4-4 on FIGUREl;

FIGURE 5 is an enlarged the line 5-5 on FIGURE 2;

FIGURE 6 is a cross-section taken along the line 6 6 on FIGURE 2.

The control unit A is illustrated in the drawings as forming part of awell packer B, which is adapted to be anchored in packed-oli conditionin a well casing C, being movable through the latter by means of atubular string D, such as tubing or drill pipe, extending to the top ofthe well bore. It is to be understood, however,

cross-section taken along 2 that the control unit A can be used in otherrelationships than the one specifically illustrated.

The well packer B shown in the drawings includes a tubular body lo, thelower end of which is .threadedly attached to a lower body guide 11, andthe upper end of which is threadedly attached to an upper body coupling12, which is, in turn, threadedly secured to the lower end of the tubingstring D that extends to the top of the well bore. Surrounding the body10 of the tool is a packingstructure 13, such as a rubber or rubber-likepacking sleeve, the lower end of which is adapted to engage the upperend of the guide 11, and the upper end of which is secured to anexpander 14, slidably mounted on the body of the tool. Any suitable modeof attachment may be used, As shown, an end ring 1S is molded to theupper portion of the packing sleeve 13, this ring being threaded withina coupling sleeve 16 threadedly secured to the lower portion of theexpander 14.

The expander 14 has a plurality of circumferentially spaced expandersurfaces 17 which are inclined in an upward and inward direction forengagement with companion tapered inner surfaces 18 on a set ofcircumerentially spaced slips 19 shiftable relative to the body 10 ofthe tool. These slips 19 have external wickers 19a facing in an upperdirection to embed themselves in the wall of the well casing C when theexpander 14 moves upwardly relative to the slips to expand the latter0utwardly. To secure retraction of the slips 19 upon relative downwardmovement of the expander 14 with respect thereto, the slips are panderby a slidable tapered spline connection. As specifically shown, theslips are mounted in slots 20 in the expander 14, the expanders havinginclined grooves 21 at the sides ofeach slot receiving inclined tongues22 projecting from opposite sides of each slip Thus, upon relativedownward movement of the expander 14 with respect to the slips 19, afterthe latter have occupied an outward expanded position, the tongue andgroove connection 22, 21 will result in a positive inward shifting ofthe slips, to place them in their retracted position.

The slips 19 are coupled together for joint movement by being secured toa slip ring 23, the slips, however, being shifted radially with respectto the ring, Such coupling and radial shifting is secured by forming theupper portions of the slips as T-shaped heads 24 shiftable within lowerslots 25 within the slip ring 23, the

upper portion of each head being slidable radially within the grooves 26opening into the sides of each slot 25.

The slip ring 23 is coupled to the control unit clutch or lock device Awhich will determine the ability of the body 1l) of the tool to movelongitudinally relative to the slip ring 23 and the slips 19 themselves.The control unit or clutch device includes a clutch or control sleeve 28coupled to the slip ring by a two-piece tie ring 29 having upper andlower flanges 31 received within upper and lower grooves 32 in the slipring 23 and the clutch sleeve 28. This tie ring is held in assembledposition by a clutch housing 33, the lower portion of which rests upon ashoulder 34 on the tie ring and en- Compasses the upper part of thelatter. This clutch housing has an upper threaded portion 35 threadedlysecured to the upper part of the clutch sleeve 23 and also threadedlysecured to the lower end of the drag body 36 of a drag device 36asurrounding the packer body 10.

each interconnected to the ex-v The clutch sleeve has an arcuate opening37 therethrough in which a clutch segment or dog 38 is disposed that iscapable of shifting radially of the sleeve 2%, being conned in suchshifting movement by the upper and lower sides 39 of the opening. Theclutch dog 3S is shiftable inwardly by a helical compression spring do,the outer end of which engages the housing 33 and the inner end of whichis disposed within a dog socket 41, engaging the inner portion of thelatter. The clutch segment 3S is urged inwardly to place its internaldownwardly facing ratchet teeth 42 into engagement with companionupwardly facing ratchet teeth 43 provided on the packer body lt?, toprevent the body from moving upwardly relative to the clutch segmentwhenever the teeth are coengaged. The arcuate body teeth 43 form alongitudinal row of teeth which extend a substantial distance lengthwiseof the body of the tool, so that the body can occupy a plurality ofpositions within the clutch sleeve 28 and clutch housing 33 and yetbecome coupled to the dog 38. The body 10 can shift downwardly freely,ratcheting along the clutch dog 3S.

The clutch dog 3S is releasable from the body clutch teeth 43 wheneverthe body lil is to be moved upwardly within the clutch sleeve 28 andclutch housing 33. lt will be noted that the body ratchet teeth 43extend only partially around the packer body 10. Between the ends of thearcuate body ratchet teeth, the packer body has a smooth oruninterrupted surface 45. Such smooth portion may be considered to be aearn or unclutching portion 4S, the purpose of which is to cam or shiftthe clutch segment 38 radially outwardly and enable the body 1d to movelongitudinally in both directions within the clutch segment or dog 38,the clutch sleeve 28 and the surrounding housing 33. Assuming theratchet teeth 42, 43 to be coengaged, the clutch dog 33 can be releasedfrom the body ratchet teeth 43 by turn-ing the body l@ of the packer tothe right, or in a clockwise direction, until the cam or smooth portion4S of the body engages the clutch segment 38 and shifts it radiallyoutward and holds it in such radial outward position. Relative rotationof the body l to the lett, or in a counter clockwise direction, willagain place the ratchet teeth 43 in position to be engaged by thecompanion inner teeth 42 on the clutch segment 38, whereupon the clutchis in the engaged position.

The location of the body ratchet teeth 43 in engagement with the clutchsegment 3S or the smooth portion 4S in engagement with the clutchsegment is determined positively. Thus, the clutch sleeve 23 has anotherextended arcuate opening 46, this opening having upper and lower sides47 and terminating at stop shoulders 4S, 49 provided by the stop sleeve.A key t) is shiftable arcuately in the opening 46, this key having aninner projection 51 slidably received within a longitudinally extendingkeyway 52 in the packer body 1t? to one side of its ratchet teeth 43. Asdisclosed most clearly in FIG. 4, when the body l@ has been turned tothe left to place the key 50 in engagement with one of the sleeve stopshoulders 49, the body ratchet teeth 43 are disposed opposite the clutchsegment 38, whereupon clutching engagement between the teeth can occur.Rotation of the body in a clockwise direction will shift the key 56arcuately in the same direction until it engages the other stop shoulder43 at the other end of the opening 46, whereupon the cam or smoothportion 45 will be disposed in confronting relation to the clutchsegment 38, insuring that the clutch segment is not in clutchingposition with respect to the body ratchet teeth 43. The body l0 can beturned to shift the key 5t) between its positions of engagement againstone stop shoulder or the other stop shoulder for different longitudinalpositions of the body with respect to the clutch structure surroundingit. Such action is permitted because of the longitudinal extent of thegroove 52 in which the inner portion 51 of the key S9 is disposed.

The ability of the clutch mechanism to be placed in its clutching orunclutching position is dependent upon the resistance to turning of theclutch sleeve 28 and housing 33 provided by the drag device 36a. Suchdrag device has the further purpose of resisting longitudinal movementof portions of the packer apparatus, such as the slip structure 23, 19,with respect to the body 10 of the tool, in order that the slips andpacking i3 can be engaged with the well casing or released therefrom.The drag device 36a includes the drag body 36 which is slidably mountedupon and with respect to the packer body lil. As stated above, the lowerportion of this drag body 34 is threadedly secured to the clutch housing33, the upper part S5 of which may be considered as constituting a stopmember or rim. The upper end 56 of the drag body may be tapered in anupward and inward direction to prevent the body 36 from hanging up onrestrictions or coupling spaces in the well casing C while being movedupwardly therein. Between its upper and lower portions the drag body hasa plurality of circumferentially spaced and longitudinally extendinggrooves 57, in each of which a drag block 58 is disposed and is radiallyslidable, the sides of the blocks being slidable along the sides of thegroove 57. Each drag block 58 has a central longitudinal portion 59adapted to frictionally bear against the wall of the well casing C,being urged outwardly against the well casing by a plurality of helicalcompression springs 6d disposed within sockets 61 in the central dragblock portion, which is located within the longitudinal groove 57, theinner ends of the springs 60 bearing against the base 62 of the groove57 and its outer end against the bases of the sockets.

From its central longitudinal portion 59 each drag lock tapers in anupward and inward direction, terminating in an upper stop member orterminal 63. Similarly, each drag blocl; tapers from its centralfriction drag portion in a downward and inward direction terminating ina lower stop terminal 64. The upper stop terminal 63 is adapted toVengage an upper stop rim or ring portion 65 of the drag body 36 and thelower stop terminal 64 is adapted to engage the lower stop rim or ring55 provided by the upper end of the stop sleeve or clutch housing 33.The engagement of the terminals 63, 64 with the stop rims 65, 55 limitsthe extent of outward movement of each drag block 5S under the inlluenceof the springs 60. When the apparatus is disposed within a well casingC, the drag blocks are shifted inwardly against the compressive force ofthe springs 60, to locate the stop terminals 63, 64 inwardly and awayfrom the upper and lower stop rims 65, 55.

ln the use of the apparatus specitically illustrated in the drawings,the packing sleeve 3 and slips 19 initially occupy their retractedpositions, the body 10 being disposed relatively downward of the partsthat surround it, and with the upper portion of its ratchet teeth 43disposed opposite the clutch dog or segment 33. The apparatus is nowinserted in the well casing C and is lowered downwardly therethrough bymeans of the tubular string D. During such downward movement the ratchetteeth 42, 43 need not necessarily be in a position to coengage, inasmuchas downward shifting of the body 10 tends to retain the packing sleeve13 and the slips 19 in their retracted positions. However, as aprecaution, it may be desirable for the ratchet teeth to be disposedopposite the clutch segment as determined by engagement of the key 50with the stop shoulder 49. Accordingly, if the body 10 of the packerwere to be shifted upwardly inadvertently to a substantial extent, theslips i9 and packing 13 would not be expanded against the well casing C.Upon insertion of the apparatus B in the well casing, the drag blocks 58are forced inwardly of the body 36 against the action of the springs 60,being guided in such movement by the side walls of the longitudinalgrooves 57.

The apparatus is now lowered in the well casing, a shoulder S0 on thepacker body 10 engaging the ring 15 to force the expander 14 downwardly,such downward movement of the expander being transmitted throngh thetongue and groove connection 22, 21 to the slips 19, which are in aretracted positon, pulling the latter downwardly, which, in turn, exerta pull upon the slp ring 23, clutch sleeve 28, the clutch housing 33 andthe drag body 36, which will force the drag blocks 58 downwardly alongthe wall of the well casing C, the drag blocks sliding frictionallyalong such wall. When the location in the casing is reached at which thepacker B is to be et, the tubular string D and body 1b are turned in aright hand d rection. In view of the frictional resistance to turningoffered by the drag blocks 58 against the well casing C, the drag body36, clutch housing 33 and clutch sleeve 28 are prevented from turning,the body 10 turning until its cam or smooth portion 45 engages theclutch segment 38 and shifts it in a radial outward direction -againstthe force of the segment spring 40. The body will turn untl its key 5i?engages the other stop shoulder 48, which definitely locates the entiresmooth cam portion 45 opposite the clutch segment 38 which is theunclutching position of the apparatus (FIG. 5).

With the parts in such position, the tubing string D and the packerbodyA are now elevated, the frictional engagement of the drag blocks 58aga nst the well casing resisting and preventing upward movement of theparts that surround the body 19. Upward movement of the body will firstengage the lower guide or abutment 11 with the lower end of the packingsleeve 13, shifting the latter upwardly, which will also shift theexpander 14 upwardly within the slips 19, the latter being preventedfrom moving upwardly by being coupled to the drag assembly 36a. Upwardmovement of the expander 14 will occur to the extent at wh ch it expandsthe slips 19 outwardiy into anchoring engagement with the well casing C.A continuation of the upward movement of the body 1t) will now move thelower abutment 11 toward the expander 11i or upper abutment, toforeshorten the packing sleeve 13 and compress it into sealingengagement with the wall of the well casing C. The Well packer has nowbeen anchored in packed-off position with the Well casing C, so thatiluid under pressure can now be pumped down through the tubular str ng Dand the packer body 1) for the performance of the desired operation inthe well bore. The pressure below the apparatus will act upwardly on thepacking structure 13 tending to seal it more firmly against the wall ofthe well casing C, and also exerting an upward force on the expander 14to Wedge it more firmly behind the slips 19 to embed their wickers inthe casing, thereby insuring aga nst upward shifting of the packer inthe well casing by the hydraulic forces acting thereon from below. n

When the packer parts are to be retracted, all that is necessary to dois to shift the tubing string D and body 1t) downwardly. The frictiondrag assembly 36a engages the wall of the well casing C to res stdownward movement of the clutch mechanism A surrounding the body 1t) andthe slip 19. Accordingly, the body 10 will move downwardly to shift thelower abutment 11 away from the expander 14 allowing the packingstructure 13 to retract inherently to its initial position. The bodyshoulder Si) will then engage the ring attached to the expander 14through the threaded coupling r16, to move the expander 14 downwardlyrelatve to the slips 19, downward movement of the latter still beingresisted by the friction of the drag block device against the casing C.In view of the tongue and groove connection between the expander 14 andslips 19, the slips are shifted to their retracted position.

The body 10 of the tool can now be turned to the left, to dispose itsratchet teeth 43 once again opposte the clutch segment 38 as determinedby engagement of the key 50 with the other stop shoulder 49. whereuponthe apparatus can be elevated in the well bore, the clutch teeth 42, 43coengaging and coupling the body lil 6 through the segment 3S to theclutch sleeve 28 and clutch housing 33, which is connected to the dragbody 36. The entire apparatus is now elevated in the Well casing C, andmay be removed entirely therefrom, the drag blocks 58 sliding frctionally against the Wall of the Well casing during such elevation ofthe apparatus.

The inventor claims:

1. In a well tool for operation in a well bore: a body memberconnectible to a running-in string for moving the tool within the Wellbore; a clutch member slidable 1on gitudinally on said body member; oneof said members having a plurality of clutch teeth disposed along thelength of said one member and about a portion of its circumference; aclutch element on the other of said members having clutch teeth adaptedto mesh with said other clutch teeth to couple said members forlongitudinal movement together when said members occupy one relativeposit on; said one member havinga smooth surface extending alongsidesaid clutch teeth on said one member about another portion of itscircumference and movable into engagement with said clutch element uponrelative angular movement between said members to another relativeposition to uncouple said members from each other, the teeth on sa dclutch element being cir'- cumferentially displaced from the teeth onsaid one member when the members occupy Vsaid another relative position,whereby said clutch element teeth and teeth on said one member areprevented from meshing with each other.

2. In a well tool adapted for operation in a well bore: a body memberconnectible to a running-in string for moving the tool w thin the wellbore; a clutch member slidable longitudinally on said body member; oneofsaid members having a plurality of one-way ratchet teeth disposed alongthe length of said one member; a clutch element on the other of saidmembers and having companion one-Way ratchet teeth adapted to mesh withsaid other ratchet teeth to couple said members for longitudinalmovement together when sa'd members occupy one relative position; saidone member having a smooth surface extending alongside said ratchetteeth on said one member about another portion of its circumference andmovable into engagement with said clutch element upon relative angularmovement between said members to another relat ve position to uncouplesaid members from each other, the teeth on said clutch element beingcircumferentially displaced from the teeth on said one member when themembers occupy said another relative position, whereby said clutchelement teeth and teeth on sald one member are prevented from meshingwith each o er.

3. In a well tool for operation in a well bore: a body memberconnectible to a running-'n string for moving the tool within the wellbore; a clutch member slidable longitudinally on said body member; oneof said members having a plurality of clutch teeth disposed along thelength of said one member and about a portion of its circumference; aclutch element on the other of said members having clutch teeth adaptedto mesh wth said other clutch teeth to couple said members forlongitudinal movement together when said members occupy one relativeposition; said one member having a smooth surface extending alongsidesaid clutch teeth on said one member about another portion of itscircumference and movable into engagement wth said clutch element uponrelative angular movement between satid members to another relativeposition to uncouple said members from each other, the teeth on saidclutch element being circumferentially displaced from the teeth on saidone meniber when the members occupy said another relative position,whereby said clutch element teeth and teeth on sa d one member areprevented from meshing with each other; and locating means forselectively positioning said members in said one relative position or insaid another relative position.

4. In a well tool adapted for operation in a well bore: va body memberconnectible to a running-in string for moving the tool within the wellbore; a clutch member slidable longitudinally on said body member; oneof said members having a plurality of one-way ratchet teeth disposedkalong the length of said one member; a clutch element on the other ofsaid members and having companion one-way ratchet teeth adapted to meshwith said other ratchet teeth to couple sa'd members for longitudinalmovement together when said members occupy one relative position; saidone member having a smooth surface extending alongside said ratchetteeth on said one member about another portion of its circumference andmovable into engagement with said clutch element upon relative angularmovement between said members to another relative position to uncouplesaid members from each other, the teeth on said clutch element beingcircumferentially displaced from the teeth on said one member when themembers occupy said another relative position, whereby said clutchelement teeth and teeth on said one member are prevented from meshingwith each other; and locating means for selectively positioning sa`dmembers in said one relative position or in said another relativeposition.

5. In a well tool adapted for operation in a well bore: a body memberconnectible to a running-'n string for moving the tool within the wellbore; a clutch member slidable longitudinally on said body member; oneof said members having a plurality of clutch teeth disposed along thelength of said one member and about a portion of its circumference; aclutch element movable laterally on the other of said members and havingclutch teeth adapted to mesh with said other clutch teeth to couple saidmembers for longitudinal movement together when said members occupy onerelative position; said one member having a smooth surface extendingalongside said clutch teeth on said one member about another portion ofits circumference and movable into engagement with said clutch elementupon relative rotation between said members to another relative positionto uncouple said members from each other, the teeth on said clutchelement being circumferentially displaced from the teeth on said onemember when the members occupy said another relative position, wherebysaid clutch element teeth and teeth on said one member are preventedfrom meshing with each other, said clutch element moving laterally ofsaid members in being shifted from a position in engagement with saidclutch teeth on said one member to a position in engagement with saidsmooth surface.

6. In a well tool adapted for operation in a well bore: 'a body memberconnectible to a running-in string for moving the tool within the wellbore; a clutch member slidable longitudinally on said body member; oneof said members having a plurality of clutch teeth disposed along thelength of said one member and about a portion of its circumference; aclutch element movable laterally on the other of said members and havingclutch teeth adapted to mesh with said other clutch teeth to couple saidmembers for long'tudinal movement together when said members occupy onerelative position; said one member having a smooth surface extendingalongside said clutch teeth on said one member about another portion ofits circumference and movable into engagement with said clutch elementupon relative rotation between said members to another relat've positionto uncouple said members from each other, the teeth on said clutchelement being circumferentially displaced from the teeth on said onemember when the members occupy said another relative position, wherebysaid clutch element teeth and teeth on said one member are preventedfrom meshing with each other, said clutch element moving laterally ofsaid members in being shifted from a position in engagement with saidclutch teeth on said 'one member to a position in engagement with saidsmooth surface; and locating means for selectively po- 8 sitioning saidmembers in sa'd one relative position or in said another relativeposition.

7. In a well tool adapted for operation in a well bore: a body memberconnectible to a running-inn string for moving the tool within the wellbore; a clutch member sl dable longitudinally on said body member; saidbody .member having a plurality of clutch teeth disposed along thelength of said body member and about a portion of its circumference; aclutch element movable laterally on said clutch member and having clutchteeth adapted to mesh with said other clutch teeth to couple saidmembers for longitudinal movement together when said members occupy onerelative position; said body member hav ng a smooth surface extendingalongside said clutch teeth on said body member about another portion ofits circumference and movable into engagement with said clutch elementupon relative angular movement between said members to another relativeposition to uncouple said members from each other, the teeth on saidclutch element being crcumferentially displaced from the teeth on saidbody member when said members occupy said another relative position,whereby said clutch element teeth and body member teeth are preventedfrom meshing with each other.

8. In a well tool adapted for operation in a well bore: a body memberconnectible to a running-in string for moving the tool within the wellbore; a clutch member sl dable longitudinally on said body member; saidbody member having a plurality of one-way ratchet clutch teeth disposedalong the length of said body member and about a portion of itscircumference; a clutch element on said clutch member and having one-wayratchet teeth companion to and adapted to mesh with said other clutchteeth to couple said members for longitudinal movement together whensaid members occupy one relative position; sa d body member having asmooth surface extending alongside said ratchet teeth on said bodymember about another portion of its circumference and movable intoengagement with said clutch element upon relative angular movementbetween said members to another relative position to uncouple saidmembers from each other, the teeth on said clutch element being crcumferentially displaced from the teeth on said body member when saidmembers occupy said another relative position, whereby said clutchelement teeth and body member teeth are prevented from meshing with eachother.

9. In a well tool adapted for operation in a well bore: a body memberconnectible to a running-in string for mov ng the tool within the wellbore; a clutch member slidable longitudinally on said body member; saidbody member having a plurality of clutch teeth disposed along the lengthof said body member and about a portion of its circumference; a clutchelement movable laterally on said clutch member and having clutch teethadapted to mesh with said other clutch teeth to couple said members forlongitudinal movement together when sa'd members occupy one relativeposition; said body member having a smooth surface extending alongsidesaid clutch teeth on said body member kabout another portion of itscircumference and movable into engagement with said clutch element uponrelative angular movement between said members to another relativeposition to uncouple Said members from each other, the teeth on saidclutch element being circumferentially displaced from the teeth on saidbody member when said members occupy said another relative position,whereby said clutch element teeth and body member teeth are preventedfrom meshing with each other; and locating means for selectivelypositioning said members in said one relative position or in saidanother relative position.

10. In a well tool adapted for operation in a well bore: a body memberconnectible to a running-in string for moving the tool within the wellbore; a clutch member slidable longitudinally on said body member; saidbody member having a plurality of one-way ratchet clutch teeth disposedalong the length of said body member and about a portion of itscircumference; a clutch element on said clutch member and having one-wayratchet teeth companion to and adapted to mesh with said other clutchteeth to couple said members for longitudinal movement together whensaid members occupy one relative position; said body member having asmooth surface extending alongside said ratchet teeth on said bodymember about another portion of its circumference and movable intoengagement with said clutch element upon relative angular movementbetween said members to another relative position to uncouple saidmembers from each other, the teeth on said clutch element beingcircumferentially displaced from the teeth on said body l@ member whensaid members occupy said another relative position, whereby said clutchelement teeth and body member teeth are prevented from meshing wjth eachother; and locating means for selectively positioning said members insaid one relative position or in said another relative position.

References Cited in the ie of this patent UNITED STATES PATENTS ConradAug. 13, 1957

